I've had the same error message, for a short while, but after upgrading (note previous versions):

--> Working on bignum
Fetching http://www.cpan.org/authors/id/P/PJ/PJACKLAM/bignum-0.67.tar.
+gz ... OK
Configuring bignum-0.67 ... OK
==> Found dependencies: Math::BigRat
--> Working on Math::BigRat
Fetching http://www.cpan.org/authors/id/P/PJ/PJACKLAM/Math-BigInt-2.00
+3001.tar.gz ... OK
Configuring Math-BigInt-2.003001 ... OK
Building and testing Math-BigInt-2.003001 ... OK
Successfully installed Math-BigInt-2.003001 (upgraded from 0.2614)
Building and testing bignum-0.67 ... OK
Successfully installed bignum-0.67 (upgraded from 0.51)
2 distributions installed
[download]

there is no error afterwards. The previous versions mentioned are not part of Perl standard distribution (no error with unpacked original Perl), but perhaps installed some time ago. Now I have erroneous versions overwritten and, honestly, no desire to dig/debug further.